Polyhydroxyalkanoates are biodegradable and biocompatible thermoplastic materials that can be produced from renewable resources and that have a broad range of industrial and biomedical applications. Polyhydroxyalkanoates can be produced as homopolymers, such as poly-3-hydroxybutyrate (also termed “PHB”) and poly-4-hydroxybutyrate (also termed “P4HB”), or as copolymers, such as poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (also termed “PHB-co-4HB”). Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymers are of interest for their potential to be produced from renewable resources and to be used for conferring rubber-like elasticity in polymer blends. Thus, for example, production of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with high amounts of 4HB monomer incorporation into the copolymer has been described previously in the literature using various microorganisms, but this was accomplished only when immediate precursors of 4-hydroxybutyryl-CoA, such as e.g. 4-hydroxybutyrate, γ-butyrolactone, and/or 1,4-butanediol were supplied with other carbon sources. E.g., Kunioka et al., Polymer Communications 29:174-176 (1988); Doi et al., Polymer Communications 30:169-171 (1989); Kimura et al., Biotechnol. Letters 14(6):445-450 (1992); Nakamura et al., Macromolecules 25(17):4237-4241 (1992); Saito and Doi, Int. J. Biol. Macromol. 16(2):99-104 (1994); Lee et al., Biotechnol. Letters 19(8):771-774 (1997); Choi et al., Appl. Environm. Microbiol. 65(4):1570-1577 (1999); Hsieh et al., J. Taiwan Inst. Chem. Engin. 40:143-147 (2009). Production of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer from glucose as a sole carbon source in genetically engineered Escherichia coli cells has also been accomplished, but the reported monomeric molar percentages of 4-hydroxybutyrate monomers of the resulting copolymers have been low, e.g. 12.5% or less during stationary phase, unless other carbon sources were co-fed. Chen et al., U.S. Pub. No. 2012/0214213; see also Dennis and Valentin, U.S. Pat. No. 6,117,658; Valentin and Dennis, J. Biotechnol. 58:33-38 (1997), Chen et al., Chinese Patent Application CN 102382789 A; Li et al., Metab. Eng. 12:352-359 (2010). Production of poly-4-hydroxybutyrate homopolymer from a genetically engineered microbial biomass metabolizing a renewable feedstock, such as glucose, has also been described, but exemplary poly-4-hydroxybutyrate homopolymer titers were less than 50% by weight of biomass titers, and in any case poly-4-hydroxybutyrate homopolymer does not have the same properties as poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer. Van Walsem et al., WO 2011/100601.